Clown Triggerfish

The clown triggerfish is a fish which grows up to 50 cm (19.7 inches) in the wild, however not typically reaching this length in captivity. Its body has a stocky appearance, oval and compressed laterally in form. The head is large and represents approximately one third of the body length. The mouth is small, terminal and has strong teeth.

The first dorsal fin is composed of three spines, one of which is longer and stronger. It is erectile and hidden in a dorsal furrow. This set of dorsal spines composes a trigger system which is a characteristic from the family Balistidae. The second dorsal fin is similar in shape and size to the anal fin which is symmetrically opposed to it. The pelvic fin is reduced to a ventral protrusion.

The clown triggerfish is widely distributed throughout the tropical and subtropical waters of the Indian Ocean and in the western Pacific Ocean.

A single record was reported in the Mediterranean Sea in Spanish waters in 2012, a likely aquarium release. It is most commonly found along external reef slopes with clear water with a depth of 1–75 m. Juveniles usually stay below depths of 20 m, and inhabit caves or overhangs.

The clown triggerfish has also been documented in the Red Sea. This was also most likely due to an aquarium release.

Balistoides conspicillum has a varied diet based on different benthic organisms like molluscs, echinoderms, crustaceans and tunicates. They have also been recorded feeding on crinoids.

The clown triggerfish is naturally diurnal, solitary and territorially defensive, making it an elusive find in its habitat. It can be very aggressive with other fish and congeners. Juvenile clown triggerfish are notably more sociable, becoming progressively less sociable and more aggressive as they age.

The first long dorsal spine is erected to impress an opponent or deter a predator, preventing it from being pulled out of its shelter.

When the clown triggerfish is in danger it hides in holes. It is capable of locking the spine on their dorsal fin in place, while also locking their smaller dorsal and ventral fin in place. This makes it harder for the fish to be pulled out of their hiding hole.

The clown triggerfish is of least concern, however, this fish has been introduced into different ecosystems in different parts of the world. One place in particular is the Red Sea, in which the clown triggerfish was introduced, most likely intentionally, by a private aquarium keeper. This sea has a fragile ecosystem that has been under considerable stress from human impacts. One of the concerns is that the clown triggerfish that have been released into the wild may contain harmful bacteria that can impact wild fish.